IRLF 


B    3    3bO 


-HELLS 


01X10 


BIOLOGY 
LIBRARY 


r 


I 


MONOGRAPH 


OF   THE 


FLUVIATILE    BIVALVE    SHELLS 

OF    THE    RIVER    OHIO, 


Genera  &  £bf  pt£«rf&fit  Species. 


Translated  from  the  French  of  C.  S.  RAFINESQUE,  Prof.  Bot 
and  Nat.  Hist,  in  Transylvania  University. 


PHILADELPHIA  : 

J.  DOBSON,  108  CHESNUT  STREET. 
1832. 


LIBRARY 


•  *     •    •  i 
*  •'  *• 


Adam  Waldie,  Printer. 


TO 


WILLIAM  HEMBEL,  ESQUIRE, 


ONE   OF    THE   VICE    PRESIDENTS  OF  THE  ACADEMY    OF  NATURAL 
SCIENCES   OF    PHILADELPHIA,  &C. 


DEAR  SIR, 

In  publicly  addressing  to  your  notice  a  trans- 
lation of  Prof.  RAFINESQUE'S  Monograph  of  the 
bivalve  shells  of  the  river  Ohio  and  its  -tributa- 
ries, it  seems  proper  to  remark,  that  this  paper 
was  originally  published  at  Brussels,  in  Septem- 
ber, 1820,  in  "  les  Annales  generales  des  Sciences 
physiques."  Extra  copies  were  transmitted  to 
the  author  in  this  country,  who  distributed  them 
among  individuals,  and  the  libraries  belonging  to 


M94104 


IV 

scientific  institutions  in  this  city  and  elsewhere. 
It  is  therefore  a  curious  circumstance  in  the  his- 
tory of  American  Conchology,  that  this  singular 
evidence  of  the  author's  acumen,  zeal  and  indus- 
try, should  thus  have  existed  for  more  than  eleven 
years,  while  but  four  of  the  numerous  species 
discovered  and  described  by  him,  are  known  by 
his  names,  either  in  the  works  of  American 
authors  or  in  our  collections. 

You  will  perceive,  that  the  definitions  as  to 
positions  of  the  parts  of  the  animal,  in  relation 
to  its  shelly  covering,  now  understood  and 
adopted  by  several  eminent  naturalists,  whose 
knowledge  and  opinions  of  their  anatomical 
structure  are  esteemed  authentic,  have  been  em- 
ployed by  Mr.  RAFINESQUE  ;  thus,  when  the  shell 
is  held  so  as  to  bring  the  apices  or  beaks  upper- 
most, and  the  ligament  between  them  and  the 
eye,  it  presents  also  the  dorsal  or  hinge  margin  : 
this  is  nearly  the  natural  position  of  the  shell ; — 


the  margin  or  edge  opposite  to  this,  is  the  basal 
margin  ;  that  in  front,  the  anterior  margin ;  and 
that  portion  of  the  shell  nearest  to  the  observer, 
the  posterior  margin.  When  the  shell  is  held  in 
this  manner,  the  right  and  left  valves  are  also 
determined  by  their  relative  position  to  that  of 
the  observer. 

At  the  same  time  that  Mr.  RAFINESQUE  sub- 
divides the  species  into  genera  and  sub-genera, 
he  likewise  retains  throughout  the  work,  for  rea- 
sons assigned  in  his  preliminary  remarks,  the 
genus  UNIO  as  established  by  BRUGUIERE  ;  this 
arrangement  will  be  found  satisfactory,  because 
it  prevents  ambiguity,  and  will  enable  the  student 
to  adopt  his  generic  terminology  at  discretion. 

I  have  much  pleasure  in  stating,  that  most  of 
the  Shells  described  in  the  following  pages,  have 
been  placed  in  my  cabinet  by  Mr.  RAFINESQVE, 
with  his  labels  and  references. 


VI 

A  desire  to  facilitate  the  study  of  this  interest- 
ing branch  of  American  Conchology,  was  my  in- 
ducement to  undertake  this  translation.  It  is  a 
fascinating  subject,  and  has  afforded  me  many 
hours  of  pleasing  and  instructive  recreation.  Be 
pleased  to  accept  it,  as  a  testimonial  of  my 
respect  for  your  zeal  and  liberality  in  the  pro- 
motion of  the  cause  of  natural  science. 

C.  A.  POULSON. 

Philadelphia,  October,  1831. 


EXPLANATION  OF  THE  PLATE. 


The  accompanying  figure  of  the  UNIO  VERRUCOSA  OF 
RAF.  (described  page  37)  is  intended  to  illustrate  the  fol- 
lowing parts  of  the  Unio: — From  A  to  D  the  dorsal  or 
hinge  margin,  which  comprises  the  beaks  or  apices,  as 
well  as  the  ligament;  D  to  B  the  anterior  margin;  A  to 
C  the  posterior  margin ;  and  C  to  B  the  basal  margin. 
The  right  valve  is  represented. 


MONOGRAPH,   &c. 


THE  numerous  fresh- water  and  terrestrial  shells 
which  inhabit  the  interior  of  North  America,  had 
not  been  observed  nor  described  when  I  under- 
took this  task  in  the  years  1818  and  1819.  I  was 
surprised  and  delighted  to  find,  that  they  were 
nearly  all  new  species,  differing  entirely  from 
those  found  in  the  vicinity  of  the  Atlantic ;  so 
that  it  appears  the  chain  of  the  Allegheny  moun- 
tains which  divides  the  country,  forms  a  distinc- 
tive line  between  the  fish  and  shells  of  the  waters 
of  the  Ohio  and  its  tributaries,  and  those  of  the 
rivers  emptying  into  the  Atlantic  ocean.  Though 
very  far  from  having  exhausted  the  study  of  the 
shells  of  this  region,  I  have  however  observed 
there,  collected  and  figured,  about  one  hundred 
and  eighty  species;  of  these  nearly  seventy  are 
fluviatile  univalves  ;  fifty  terrestrial  univalves  and 
sixty  fluviatile  bivalves.  I  now  propose  to  de- 
scribe the  latter,  the  univalves  will  be  described 
elsewhere.  I  have  already  published  many,  and 
particularly  the  new  Genera,  in  my  Prodromus 
of  the  new  animals  of  North  America. 

The  greater  number  of  the  bivalves  of  the  Ohio 
are  found  also  in  most  of  its  tributary  streams, 
2 


: :it       10 

such  as  the  Kentucky,  Cumberland,  Tennessee, 
Wabash,  Miami,  Green,  Scioto,  Licking,  Musk- 
ingum,  Kenhawa,  &c.  many  of  which  are  con- 
siderable rivers,  of  from  five  to  eight  hundred 
miles  in  length.  It  remains  to  be  ascertained 
whether  they  are  common  to  the  whole  of  the 
valley  of  the  Mississippi,  to  the  Missouri,  Ark- 
ansa,  &c.  I  am  certain  some  have  been  found 
there,  and  think  it  probable  that  the  shells  of  this 
immense  basin  are  analogous,  although  many 
particular  species  may  be  discovered  hereafter  in 
the  great  western  and  southern  branches  of  these 
rivers. 

Among  the  bivalves  of  the  Ohio,  the  greater 
portion  of  the  species  belong  to  the  genus  Unio, 
as  now  established.  A  number  of  species,  so 
great  as  to  quadruple  this  genus,  presenting  in- 
finite anomalies  in  form  and  structure,  is  a  very 
remarkable  fact,  and  occasioned  doubts  respect- 
ing the  annunciation  of  its  characters.  Struck  at 
first  by  some  differences  in  the  animals  inhabiting 
these  shells,  1  thought  I  could  distinguish  a  new 
family  or  a  new  genus,  which  I  proposed  to  name 
Potamila.  I  was  afterwards  convinced,  that  not- 
withstanding the  slight  differences  in  the  animals, 
these  shells  accorded  entirely  with  the  generic 
character  of  the  Unio,  but  at  the  same  time  exhi- 
biting well  defined  secondary  characters,  such  as, 
transverse  or  longitudinal  shells,  with  forms  either 


11 

elliptical,  triangular,  square,  oboval,  rounded,  &c. 
and  with  the  lamellar  tooth,  either  horizontal,  ob- 
lique, vertical,  straight,  curved,  flexuous,  &c.  In 
my  Prodromus  of  seventy  new  genera,  I  proposed 
to  divide  them  into  eight  sub-genera.  Since  that, 
having  increased  the  number  of  my  species,  it 
seemed  proper  to  construct  several  genera  and 
sub-genera ;  I  however  give  the  name  Unio,  in 
the  second  place,  to  all  my  new  species,  in  con- 
formity with  the  views  of  naturalists,  who  hesitate 
in  adopting  the  changes  in  nomenclature  which 
discoveries  render  necessary  ;  remarking,  that  by 
admitting  all  of  them  into  the  genus  Unio,  which 
will  then  consist  of  more  than  seventy  species,  it 
would  be  requisite  to  repeat,  in  the  description  of 
their  specific  characters,  that  of  the  characters  of 
my  new  genera,  which  would  render  the  defini- 
tion of  the  species  prolix. 

Of  the  Unios  of  North  America  mentioned  by 
authors,  one  was  discovered  by  the  younger 
MICHAUX  in  the  Ohio,  and  in  the  account  of  his 
travels  it  is  named  U.  Ohiensis,  but  as  it  is  not 
described,  I  cannot  refer  it  to  any  of  my  species  : 
besides,  the  name  is  unsuitable ;  it  is  singular 
that  he  found  but  one  in  that  river,  which  has 
produced  upwards  of  fifty  species !  The  Unio 
Caroliniana  of  Bosc  is  imperfectly  described  ; 
however,  I  presume  that  it  is  not  identical  with 
any  species  of  the  Ohio.  Among  the  new  species 


12 

of  Unios  described  by  SAY,  in  Nicholson's  Dic- 
tionary (American  edition)  Art.  Conchology, 
there  are  four  from  the  Ohio,  viz  : — U.  Crassus  ; 
U.  Alatus ;  U.  Ovatus,  and  U.  Cylindricus  ;  the 
description  of  the  first  one  evidently  comprises 
many  species,  improperly  blended. 

The  other  bivalves  of  the  Ohio  belong-  to  the 
genera,  Alasmodon,  Cyclas,  and  Notrema,*  which 
comprise  very  few  species. 

The  animals  contained  in  these  shells  are 
scarcely  fit  for  food,  the  taste  being  extremely 
flat  and  insipid,  and  consequently  but  little  used 
for  that  purpose.  Some  of  the  large  species, 
however,  have  an  enticing  appearance,  but  the 
only  mode  by  which  they  are  rendered  fit  for  the 
table,  consists,  in  soaking  them  for  a  time  in 
vinegar,  they  may  then  be  fried  or  soused.  Se- 
veral kinds  of  fish  feed  on  them,  especially  the 
Ambloclon  grunniens.  Herons  also  devour  them, 
when  they  cannot  procure  fish  ;  and  hogs  are  very 
fond  of  them, — herds  of  these  animals  are  often 
seen  searching  for  them  in  the  rivers,  and  are 
devoured  by  them  with  avidity,  notwithstanding 
the  hard  thick  shell  of  many  species.  The 
vulgar  names  do  not  vary  much,  they  are  all 
confounded  under  those  of  mussel,  clam,  box- 
shell,  snuff-box,  &c. 

*  Vide  supplement.— TRANS, 


13 

The  interior  of  many  species  is  adorned  with 
very  brilliant  colours,  such  as  shades  of  purple, 
violet,  copper,  pearl,  gold,  and  frequently  irides- 
cent, although  the  colour  of  the  epidermis  which 
always  covers  the  shells,  is  of  a  dark  or  black, 
brown,  chestnut,  ferruginous,  or  olive,  &c.  Many 
produce  pearls  or  pearly  and  coloured  excrescen- 
ces, some  of  which  are  very  beautiful; — their 
variegated  nacre  might  be  made  useful  and 
profitable  in  the  arts.  In  places  out  of  the  lime- 
stone region,  these  shells  are  gathered  for  the 
purpose  of  making  lime.  The  animal  is  usually 
white,  sometimes  yellow  or  saffron  coloured  ;  and 
is  very  long  lived. 

FAMILY   PEDEFERIA. 

Shell  bivalve,  equivalve,  inequilateral ;  animal 
having  a  large  compressed  foot,  tendinous,  not 
byssiferous;  two  very  short  syphons,  or  sometimes 
instead,  two  apertures;  the  anus  under  the 
ligament ;  hinge  dentated  or  lamellated. 

This  family  includes  all  the  bivalve  shells  of 
the  Ohio,  such  as  the  genera  Unio,  Anodonta,  &LC. 
of  authors ;  as  well  as  my  new  genera  separated 
from  the  Unio.  I  have  divided  it  into  several 
sub-families,  of  which  five  are  found  in  the  Ohio. 
2* 


14 
FIRST  SUB-FAMILY — UniodioB. 

Shell  transverse;  cardinal  tooth  bilobed,  an- 
terior; lamellar  tooth,  posterior,  horizontal,  or 
oblique;  apices  or  beaks  slightly  oblique ;  wrinkles 
concentric  or  zonal. 

First  Genus — UNIO. 

Shell  elliptical ;  ligament  straight ;  cardinal 
tooth  bilobed,  commonly  furrowed  or  sulcated  ; 
lamellar  tooth  horizontal,  often  straight,  never 
flexuous ;  axis  variable  ;  marginal  contour  usu- 
ally thickened ;  three  cicatrices  or  muscular 
impressions.  Animal  with  a  large  bilobed  mantle, 
not  fringed  ;  syphons  scarcely  protruding ;  with 
a  flat  bilamellar  appendage  at  the  side  of  each 
syphon ;  branchiae  striated  in  the  form  of  a 
second  interior  and  bilobed  mantle. 

It  is  thus  I  define  the  group,  to  which  I  retain 
the  name  of  Unio,  because  it  appears  to  be  the 
most  numerous,  and  resembles  that  known  by  this 
name  in  Europe ;  nevertheless  it  seems,  that  if 
these  shells  are  identically  congeneric,  the  lamel- 
lar appendages  of  the  syphons,  and  the  striated 
mantle-like  branchice,  would  have  been  noticed. 
Besides  the  three  muscular  impressions,  many 
species  have  a  muscular  fossule  or  pit  at  the 
extremity  of  the  lamellar  tooth,  which,  though 


15 

sometimes  confluent  with  the  solitary  impression 
on  this  side  of  the  shell,  is  often  distinct  from  it. 
If  this  genus  differs  in  the  animal,  from  the  Unios 
of  Europe,  it  must  be  called  Elliptic,  a  name  which 
I  have  given  to  one  of  its  sub-genera.  I  divide  it 
into  four  sub-genera. 

First  Sub-genus — ELLIPTIC. 

Shell  elliptical ;  axis  extramedial ;  cardinal 
tooth  •  furrowed  ;  contour  thickened  ;  ligament 
corneous ;  lamellar  tooth  straight. 


SPECIES  I.     Unio  Nigra — (Elliptio  Nigra.) 

Shell  oval-elliptical,  slightly  ventricose,  (bom- 
bee  /)  with  a  slight  angular  truncation  posteriorly  ; 
thick  ;  epidermis  blackish  ;  nacre  roseate  ;  lam- 
ellar tooth  thick,  obtuse,  slightly  crenulated. 
Length  T9j — diam.  T6j — axis  %  of  the  breadth. 

This  is  one  of  the  large  species  produced  in 
the  Ohio,  sometimes  measuring  six  inches  in 
breadth ;  nacre  fine,  frequently  iridescent,  as  are 
always  the  muscular  impressions  ;  fossule  distinct. 

The  following  description  of  the  form  of  the 
hinge,  applies  to  all  the  species.  Cardinal  tooth 
bilobate,  anterior,  thick,  trihedral,  furrowed,  lobes 
of  unequal  size,  the  anterior  smallest  in  the  right 
valve,  the  opposite  one  in  the  left ;  lamellar  tooth 


16 

simple  in  the  right,  which  fits  in  the  double  lamel- 
lar tooth  of  the  left  valve  ;  ligament  hard,  almost 
calcareous,  corneous  exteriorly  and  convex ;  two 
unequal  muscular  impressions  beneath  the  cardinal 
tooth,  the  second  or  inferior  smaller  than  the 
other  ;  ihefossule  forms  a  kind  of  fourth  muscular 
impression  between  the  end  of  the  lamellar  tooth 
and  its  muscular  impression,  which  is  separated 
from  it.  Apices  or  summits  of  the  valves  decor- 
ticated, and  frequently  the  shell  also ;  this  has 
been  erroneously  employed  by  conchologists  as  a 
specific  character,  as  it  exists  in  all  the  species, 
except  the  U.Jlava,  U.  viridis,  and  young  shells. 
This  effect  is  accidental  and  secondary,  and  the 
consequence  of  their  mode  of  living.  In  opening 
and  closing  the  valves,  the  animal  rubs  them 
against  the  sand  or  gravel  in  which  it  resides, 
and  thus  gradually  wears  away  the  apex;  if  it 
resides  in  mud,  the  parts  are  very  slowly  denuded, 
whilst  among  gravel  the  whole  surface  of  the 
valves  becomes  worn  and  carious.  The  contour 
of  the  marginal  edge,  is,  on  the  contrary,  quite 
entire,  and  hermetically  closed  by  a  prolongation 
of  the  membranous  and  flexible  epidermis,  which 
the  animal  forms  by  an  exudation  from  its  foot. 
No  part  of  the  shell  is  gaping,*  except  in  old 
specimens.  In  order  to  complete  the  general 

*  In  the  original  work,  the  word  "  brilliant"  is  a  mis- 
print for  "  baillant. — TRANS. 


17 

knowledge  of  these  animals,  I  subjoin  a  de- 
scription of  that  inhabiting  the  U.  nigra. 

All  the  animals  belonging  to  this  family  pre- 
sent but  slight  differences  in  colour,  dimensions, 
and  proportions. 

Body  white  or  slightly  flesh  coloured  ;  mantle 
smooth,  thin,  covering  the  valves,  bilobed  and 
posteriorly  notched,  rough,  without  fringes ;  se- 
cond mantle  interior,  branchial,  striated  obliquely, 
thin,  bilobed  posteriorly,  much  smaller  than  the 
exterior  one,  and  enveloping  the  foot ;  foot  com- 
pressed, muscular,  coriaceous,  oblong,  dilatable  ; 
mouth  anterior  ;  anus  posterior,  at  the  extremity 
of  the  ligament.  The  anterior  lateral  syphons 
equal,  one  on  each  side,  behind  the  mouth,  in  the 
form  of  a  perforated  tubercle ;  and  still  further 
back,  equally  on  each  side,  an  obtuse  bilamellar 
appendage  with  unequal  plates,  flat,  oval,  or  ob- 
long, the  interior  one  largest ;  these  are  appa- 
rently the  organs  of  generation.  From  this 
description,  the  result  of  an  accurate  examination 
of  twenty  species  and  three  hundred  individuals, 
it  will  be  perceived,  that  there  is  a  very  remark- 
able difference  between  these  animals  and  those 
of  the  European  Unios,  as  described  by  authors, 
and  particularly  by  FERRUSA.C,  (vide  Essai  d'une 
methode  conchyliogique)  who  prides  himself  on 
the  scrupulous  exactness  with  which  he  has  de- 
scribed the  fluviatile  mollusca. 


18 

These  animals  live  on  the  surface  of  the  beds 
of  rivers ;  free ;  and  resting  in  various  positions, 
on  the  side  or  vertically,  with  the  aperture  below 
or  oblique.  They  can  when  necessary  bury  them- 
selves in  the  sand  or  earth,  particularly  in  winter, 
and  even  in  summer  in  the  smaller  rivers  subject 
to  be  dried  up.  They  resist  drought  very  well. 
Their  progressive  motion  is  very  slow,  effected 
by  means  of  their  foot,  which  as  slowly  furrows 
the  ground.  They  are  hermaphrodite  and  very 
prolific,  the  eggs  are  very  small  and  enveloped 
in  a  glairy  substance,  frequently  of  a  yellow  co- 
lour. Many  young  shells  are  hatched  in  the 
shell  of  the  parent. 

This  species  has  two  varieties,  viz  : — 
Var.  1.  Fusca — deep   brown  epidermis,  pale 
nacre. 

Var.  2.  Maculata — brown  spots,  nacre  almost 
white. 


SPECIES  II.     Unio  crassa — (Elliptic  crassa.) 

Syn.  Unio  crassus.     SAY. 

Shell  elliptical,  slightly  ventricose,  very  thick ; 
epidermis  brown  ;  nacre  white ;  lamellar  tooth 
thick,  obtuse ;  wrinkles  distinct.  Length  f— - 
diam.  £ — axis  £  of  the  breadth. 

This  species  is  figured  by  Mr.  SAY  under  this 


19 

name,  but  his  description  (in  which  from  his  own 
admission  he  blends  several  species)  is  worth  no- 
thing. The  shell  is  thicker  in  this,  than  in  the 
preceding  species ;  otherwise  it  resembles  it  very 
much;  the  principal  difference  consists  in  the 
axis  being  more  lateral,  and  the  want  of  posterior 
inclination.  Breadth  from  four  to  five  inches. 


SPECIES  III.     Unio  viridis — (Elliptic  viridis.} 

Shell  elliptical,  obliquely  truncated  posterior- 
ly ;  slightly  ventricose ;  scarcely  thick ;  apices 
with  flexuous  wrinkles ;  epidermis  smooth,  olive 
green  ;  nacre  bluish  ;  cardinal  tooth  compressed, 
crenulated,  divergent.  Length  | — Diam.  -^ — 
axis  i  of  the  breadth. 

Var.  1.  radiata — radiated  with  pale  yellow. 

Var.  Z.fuscata — epidermis  brownish  olive. 

A  small  species,  at  most  an  inch  and  an  half  in 
breadth,  rare  in  the  Ohio, common  in  the  Kentucky 
and  the  small  rivers  adjacent.  Apices  seldom 
eroded,  for  they  are  thickened  by  flexuous  folds 
or  wrinkles,  remarkable  because  the  rest  of  the 
exterior  is  smooth.  The  cardinal  tooth  is  slender, 
and,  in  consequence,  becomes  crenulated  instead 
of  being  furrowed  ;  truncation  oblique,  convex  ; 
muscular  impressions  slight ;  no  fossule  ;  lamellar 
tooth  slender. 


20 
SPECIES  IV.   Unio  Fasciata — (Elliptio  Fasciata.) 

Shell    elliptical,   ventricose,    slightly    thick ; 
epidermis  slightly  rugose,  olive  coloured,   orna- 
mented with  brown  rays  ;  nacre  bluish  ;  cardinal 
tooth  rugose,  divaricated  ;  lamellar  tooth  carinated. 
Length  f — diam.  ^ — axis  £  of  the  breadth. 
Var.  1.  nisro-fasciata — dark  rays. 
Var.  2.  alternata — greenish  with  blackish  rays  ; 

alternately  broader  and  narrower. 
Var.  3.  cuprea — copper   coloured,  with    olive 

rays  ;  nacre  light  copper  colour. 
A  handsome  species,  approaching  the  U.  ochra- 
ceus  of  SAY  ;  commonly  small ;  I  have  seen  some 
specimens,  however,  more  than  three  inches 
broad.  In  the  rivers  Ohio,  Allegheny,  Musk- 
ingum,  Kentucky,  Salt,  Green,  &c.  Muscular 
impressions  slight ;  fossule  deep. 

Note. — We  should  probably  refer  to  this 
sub-genus  the  following  species  of  authors,  and 
perhaps  some  others : 

Unio  Caroliniana  of  Bosc. 

plicata  1  from  Lake  Erie — LESUEUR. 

Var.  of  U.  crassa.*     SAY. 
purptirea.*     SAY.     Pennsylvania.  . 
aurata,  a  new  species  from  the  Hud- 
son :  it  is  elliptical,  with  the  poste- 

*  U.  crassus — 17.  purpureus.     SAY. — TRANS. 


21 

rior  part  obliquely  truncated;  shell 
rather  thick;  epidermis  brown,  blackish, 
olive  and  gold  coloured  ;  tooth  small, 
rugose.  Length  4 — diam.  f — axis  £  of 
the  breadth. 
Unio  pictorum,  &c. 

Second  Sub-genus — LEPTODEA. 

Cardinal  tooth  entire  and  smooth,  that  of  the 
right  valve  simple  ;  contour  not  thickened ;  liga- 
ment membranaceous  ;  lamellar  tooth  slightly 
curved. 


SPECIES  V.     Unio  leptodon — (Elliptio  leptodon.) 

Shell  elliptical,  much  compressed,  attenuated 
posteriorly,  thin  and  fragile,  somewhat  rugose  ; 
epidermis  brownish  ;  nacre  violaceous ;  cardinal 
tooth  small,  obtuse^  smooth,  tubercular;  lamellar 
tooth  thin  and  long.  Length  ^ — diam.  J- — axis 
i  of  the  breadth. 

Common  in  the  lower  part  of  the  Ohio,  mostly 
small,  for  its  shell  is  so  fragile,  that  it  easily  be- 
comes the  prey  of  its  enemies ;  notwithstanding 
this,   it   sometimes   attains  to   three   inches   in 
breadth.     The  muscular  impressions  are  slight ; 
fossule  apparent,  confluent ;  animal  whitish. 
Var.  1.  olivacea — olive  epidermis. 
3 


22 


Var.  2.    semi-radiata,    olive     with 
rays,  brown. 


SPECIES  VI.     Uniofragilis — (Elliptic fragilis.) 

Shell  elliptical,  a  little  dilated  posteriorly,  very 
thin  and  fragile,  almost  smooth  ;  epidermis  olive  ; 
nacre  bluish  ;  cardinal  tooth  smooth,  compress- 
ed ;  lamellar  tooth  short.  Length  | — diam.  | — 
axis  i  of  the  breadth. 

Var.  l.fuscata — epidermis  reddish  brown. 

This  species  resembles  the  preceding  very 
much  ;  differing  from  it  however  in  shape,  which 
is  dilated  instead  of  being  attenuated,  slightly 
compressed  ;  ventricose,  surface  almost  smooth, 
&c.  The  apices  not  apparent ;  animal  yellowish; 
breadth  about  two  inches.  These  two  species 
nearly  resemble  the  U.  viridis,  U.fasciata,  U. 
aurata,  U.  nasuta,  &c.  which  are  also  fragile, 
but  may  readily  be  distinguished  by  their  teeth, 
which  are  very  different,  being  smooth  ;  lamellar 
tooth  somewhat  curved,  &c. 


SPECIES  VII.     Unio  nervosa — (Elliptio  nervosa.} 

Shell  elliptical,  widest  posteriorly,  thin,  with 
flexuous  nerve-like  lines,  concentric,  vermicular  ; 


23 


border  undulated  ;  epidermis  brown  ;  nacre  bluish. 
Length  | — diam.  f — axis  £  of  the  breadth. 

This  species  is  rare  and  very  distinct ;  I  have 
found  it  at  the  rapids  of  the  Ohio;  breadth  one  inch 
and  an  half.  The  cardinal  tooth  small  and  tuber- 
cular ;  lamellar  tooth  narrow  and  curved  ;  mus- 
cular impressions  slightly  apparent;  marginal 
contour  somewhat  thickened,  undulated,  and 
eroded. 

Third  Sub-genus — AXIMEDIA. 

Lamellar  tooth  slightly  curved;  axis  nearly 
medial ;  valves  almost  equilateral. 


SPECIES  VIII.  Unio  elliptica — (Elliptio  elliptica. ) 

Shell  elliptical,  angular  posteriorly,  thick,  al- 
most smooth  ;  epidermis  chestnut  brown  ;  nacre 
pale  violaceous  ;  cardinal  tooth  wrinkled,  ob- 
tuse ;  lamellar  tooth  obtuse,  thick.  Length  £ — 
diam.  f — axis  T7F  of  the  breadth. 

This  shell  is  also  rare,  found  near  Louisville 
and  Maysville,  K.  Breadth  about  two  inches  >' 
muscular  impressions  deep ;  valves  slightly  ven- 
tricose  ;  apices  prominent,  very  obtuse. 


24 


SPECIES  IX.  Unio  lavigata — (Elliptio  lavigata.} 

Shell  elliptical,  rounded,  ventricose,  thick, 
smooth  ;  epidermis  olive  ;  nacre  bluish  white  ; 
cardinal  tooth  slightly  wrinkled  ;  lamellar  tooth 
short.  Length  %— diam.  f — axis  T7F  of  the 
breadth. 

A  small  species,  at  most  an  inch  in  breadth;  it 
approaches  the  genera  Rotundaria  and  Cyclas. 
Found  in  the  Kentucky  river.  .Apices  rounded, 
prominent,  and  eroded  ;  lamellar  tooth  somewhat 
oblique.  This  species  ought  perhaps  to  belong 
to  the  sub-genus  Plagiola,  of  the  genus  Obli- 
quaria. 


SPECIES  X.   Unio  zonalis — (Elliptio  zonalis.} 

Shell  elliptical,  thick,  wrinkled;  epidermis  red- 
dish with  brown  zones ;  apices  prominent,  ven- 
tricose. Length  f — diam.  f — axis  f  of  the 
breadth. 

This  species  is  rare,  found  but  one  specimen 
at  the  falls  of  the  Ohio  ;  breadth  upwards  of  two 
inches. 

Fourth  Sub-genus — EURINEA. 

Valves  very  transversal  or  broad  ;  axis  almost 
lateral ;  ligament  very  long. 


25 


SPECIES  XL   Unio  dilatata — (Elliptic  dilatata.} 

Shell  elliptical,  oblong,  slightly  attenuated 
posteriorly,  thick,  almost  smooth  ;  epidermis  red- 
dish brown  ;  nacre  violet ;  cardinal  tooth  obtuse, 
thick ;  lamellar  tooth  very  slightly  inclined. 
Length  i — diam.  f — axis  ±  of  the  breadth. 

A  handsome  species,  very  common ;  nacre 
beautiful,  often  changeable  purple  or  bluish,  more 
or  less  deep  or  pale ;  breadth  three  to  four 
inches;  epidermis  varies  red  or  brown  ;  muscular 
impressions  striated  ;  fossule  apparent ;  cardinal 
tooth  thick,  rugose  ;  lamellar  tooth  obtuse  ;  ani- 
mal vellowish. 


SPECIES  XII.  Unio  latissima-(Elliptio  latissima.) 

Shell  elliptical-oblong,  slightly  attenuated  pos- 
teriorly, thick,  smooth  ;  epidermis  blackish  ;  nacre 
flesh  coloured,  with  a  white  margin  ;  cardinal 
tooth  obtuse,  wrinkled  ;  lamellar  tooth  carinated, 
very  straight  and  long.  Length  f — diam.  1 — 
axis  I  of  the  breadth. 

A  large  species,  attaining  eight  inches  in 
breadth  ;  not  so  common  as  the  preceding  ;  car- 
dinal tooth  somewhat  trihedral ;  muscular  im- 
•pressions  smooth  ;  fossule  slightly  marked  ;  lamel- 
lar tooth  carinated,  sharp,  thick,  horizontal  ; 
3* 


animal  white.     A  similar  species  is  found  in  the 
river  Susquehanna. 


SPECIES  XIII.   Unio  solenoides — (Elliptic 
solenoides.} 

Shell  elliptical,  cylindrical,  attenuated,  round- 
ed anteriorly ;  retuse  posteriorly ;  thick,  very 
ventricose,  with  flexuous  posterior  wrinkles  ; 
epidermis  olive  brown;  nacre  bluish  white;  cardi- 
nal tooth  rugose,  obtuse;  lamellar  tooth  very 
long,  horizontal.  Length  f — diam.  T4T — axis  T3r 
of  the  breadth. 

A  very  remarkable  species,  found  in  the  upper 
part  of  the  Ohio.  Breadth  about  three  inches ; 
apices  prominent  ;fossule  visible. 

Var.   1.  interrupta,  with  some    blackish 
lines  interrupted  or  broken  anteriorly. 
Var.  2.  nodosa — with  knots  or  nodosities 

posteriorly. 

Var.  3.   cylindricus,    SAY.     Very  thick, 
nacre  white,  apices  very  large. 

Second  Genus — LAMPSILIS. 

Shell  oval ;  ligament  curved,  cardinal  tooth 
furrowed  ;  lamellar  tooth  curved,  flexuous  ;  axis 
extramedial ;  marginal  contour  thickened  ;  three 


27 

muscular  impressions  ;  animal  similar  to  that  of 
the  Unio,  but  with  syphons  apparent,  short. 

This  name  is  modified  from  Lasmacampsilis, 
which  signifies  flexuolated  lamellar  tooth,  the 
essential  character  of  this  genus. 


SPECIES  XIV.  Lampsilis  cardium — (Unio 
cardium.) 

Shell  oval,  broad,  inclined  posteriorly,  very 
ventricose,  thick ;  apices  prominent,  heart 
shaped  ;  epidermis  reddish  brown,  rugose,  black- 
ish posteriorly  ;  nacre  white,  roseate  posteriorly. 
Length  f — diam.  f — axis  ^  of  the  breadth. 

A  beautiful  species,  very  ventricose  ;  breadth 
sometimes  six  inches  ;  cardinal  tooth  striated, 
crenulated ;  lamellar  tooth  compressed ;  animal 
white,  bi-lamdlar  appendages  broad,  exterior  la- 
mellar tooth  largest. 


SPECIES  XV.  Lampsilis  ovata — (Unio  Ovata.) 
Unio  ovatus,  SAY. 

Shell  oval,  regular,  attenuated  posteriorly, 
ventricose;  apices  prominent;  epidermis  corneous, 
brown  on  the  posterior  depression  ;  nacre  white  ; 
somewhat  thick.  Length  f — diam.  T3^ — axis  ^  of 
the  breadth. 


28 


May  not  this  be  a  variety  of  the  preceding 
species  ?  It  seems  to  differ  principally  in  shape, 
being  less  ventricose,  and  less  dilated  posterior- 


SPECIES  XVI.  Lampsilis  fasciola — (Unio 
fasciola.) 

Shell  oval,  dilated  posteriorly,  ventricose, 
somewhat  thick;  epidermis  olivaceous  with  bands, 
radiated,  flexuous,  unequal,  greenish.  Length  | 
— diam.  f — axis  ^  of  the  breadth  ;  nacre  bluish 
white. 

Rare  ;  found  in  the  Kentucky  ;  breadth  two  to 
three  inches  ;  cardinal  tooth  small,  superior  part 
furrowed,  smooth  and  inclining  inferiorly  ;  lamel- 
lar tooth  slender,  plaited.* 


*  The  two  following  species,  which  I  discovered  in  the 
Hudson  river,  ought  to  belong  to  this  genus. 

Lampsilis  rosea.  Oval,  dilated  and  truncated  obliquely, 
posteriorly  ;  shell  thick,  wrinkled ;  epidermis  olivaceous  ; 
black  posteriorly  ;  nacre  roseate ;  very  ventricose ;  apices 
prominent.  Length  5-8 — diam.  1-2 — axis  4-5  of  the 
breadth. 

Lampsilis pallida.  Oval,  dilated  and  rounded  posterior- 
ly; shell  thick,  wrinkles  separated  ;  epidermis  reddish  olive 
with  brown  rayr,  ;  oblique  posteriorly ;  nacre  white. 
Length  3-4 — diarr..  1-2 — axis  4-5  of  the  breadth. 


29 

Third  Genus — METAPTERA. 

Shell  oval,  triangular,  dilated  into  a  wing  pos- 
teriorly; ligament  inclined  over  the  wing;  cardi- 
nal tooth  bilobed,  crenulated ;  lamellar  tooth 
curved,  detached  from  the  edge  of  the  wing; 
axis  extramedial ;  contour  slightly  thickened; 
three  muscular  impressions;  animal  resembles 
that  of  the  Unio. 

The  name  signifies  posterior  wing  ;  I  at  first 
adopted  that  of  Proptera,  erroneously,  because  it 
signifies  anterior  wing. 


SPECIES  XVII.  Metaptera  megaptera — (Unio 
megaptera.) 

Shell  thin,  compressed ;  epidermis  brown,  flexu- 
ously  rugose ;  nacre  purple ;  wing  very  large, 
smooth  inside ;  lamellar  tooth  double  in  the  right 
valve,  and  with  an  oblong  protuberance  at  the 
extremity.  Length  f — diam.  f — axis  £  of  the 
breadth. 

A  fine  species,  common  in  the  Ohio  ;  beautiful 
nacre,  purple,  iridescent ;  frequently  with  pearli- 
form  tubercles ;  cardinal  tooth,  lobes  nearly 
equal  in  size,  smooth  exteriorly;  crenulated, 
compressed,  furrowed  interiorly  ;  anterior  muscu- 
lar impressions  strongly  marked,  striated;  the 


30 

posterior  one  almost  effaced.    Breadth  sometimes 
six  inches. 

The  U.  alatus  of  SAY,  which  is  found  in  Lake 
Erie,  appears  to  resemble  this  species,  and  to 
differ  from  it  only  in  its  wing,  which  is  rugose 
inside  ;  contour  marked,  flexuous  ;  lamellar  tooth 
simple  in  the  right  valve  ;  length  four  fifths  of 
the  breadth,  &c.  It  appears  that  the  two  follow- 
ing species  of  SAY,  should  also  be  referred  to 
this  genus,  but  he  does  not  point  out  the  lamel- 
lar tooth  as  being  flexuous. 

U.  ochraceus. 

U.  cariosus. 

Fourth  Genus — TRUNCILLA. 

Shell  semi-triangular,  axis  nearly  medial : 
ligament  oblique ;  the  truncation  plane,  oblique, 
posterior;  cardinal  tooth  smooth,  denticulated, 
compressed ;  lamellar  tooth  compressed,  oblique ; 
animal  similar  to  that  of  the  Unio. 

This  name  is  derived  from  the  remarkably 
oblique  truncation,  which  is  more  distinctly 
marked  than  in  all  the  other  species  of  this 
family. 


31 

SPECIES  XVIII.   Truncilla  triqueter — (Unio 
triqueter.} 

Shell  slightly  thick,  very  ventricose  ;  apices 
prominent ;  shape  almost  trihedral ;  posterior  part 
very  flat,  a  little  tessellated,  ventricose  ;  epidermis 
of  a  deep  olive  colour  striped  with  brown  ante- 
riorly ;  borders  and  wrinkles  flexuous  in  the  mid- 
dle ;  nacre  bluish  white.  Length  f — diam.  ^ — » 
axis  f  of  the  breadth. 

A  species  very  remarkable  and  rare,  which  I 
have  observed  only  at  the  falls  of  the  Ohio ;  its 
form  is  so  singular,  that  it  has  received  the  vul- 
gar name  of  snuff  box  ;  I  have  not  seen  the  ani- 
mal, which  I  suspect  differs  somewhat  from  that 
of  the  Unio  ;  breadth  one  and  an  half  inches,  la- 
mellar tooth  short,  broad,  and  obtuse  ;  muscular 
impressions  slightly  marked,  the  posterior  one 
very  large,  occupying  nearly  all  that  portion  of 
the  face  of  the  valves  ;  fossule  very  slight ;  edge 
or  border  slightly  flexuous. 


SPECIES  XIX.      Truncilla truncata — (Unio 
truncata.) 

Shell    slightly  thick,     somewhat    ventricose, 

slightly  square  ;  apices  prominent ;  the  posterior 

face    truncated ;    epidermis    olive ;    edge     and 

irrinkles  flexuous  posteriorly  ;  nacre  bluish  white. 


32 

Length  -f — diam.  -^ — axis  T5^  of  the  breadth. 
This  species  is  more  common  than  the  preceding, 
and  smaller,  usually  one  inch  in  breadth  ;  teeth 
broad ;  edge  sharp. 

Var.  1.  fusca,  almost  entirely  brown. 

Var.  2.  vermiculata,  with  flexuous  brown 
transverse  lines. 

Fifth  Genus — OBLIQUARIA. 

Form  variable,  often  somewhat  transverse,  and 
more  or  less  oblique  posteriorly ;  ligament 
oblique  ;  cardinal  tooth  bilobed,  commonly  fur- 
rowed ;  lamellar  tooth  oblique,  often  straight ; 
axis  variable  ;  marginal  contour  thickened  ;  three 
muscular  impressions ;  animal  similar  to  that  of 
the  Unio. 

This  group  is  numerous  in  species  ;  it  differs 
principally  from  the  Unio  or  Elliptio  in  its  form, 
by  the  ligament  and  by  the  oblique  lamellar 
tooth,  &c.  It  presents  many  anomalies,  and  secon- 
dary characters,  which  oblige  me  to  divide  it 
into  six  sub-genera. 

First  Sub-genus — PLAGIOLA. 

Axis  extramedial ;  lamellar  tooth  curved  ;  liga- 
ment curved; form  of  the  shell  variable,  but  not 
oblique. 


33 

SPECIES  XX.     Obliquaria  decorticata — (Unio 
decorticata.} 

Shell  rounded-elliptical,  thick  and  very  ven- 
tricose  ;  apices  prominent ;  epidermis  blackish, 
nearly  detached ;  wrinkles  separated ;  nacre 
white.  Length  f — diam.  1 — axis  about  i  of 
the  breadth. 

I  have  observed  this  species  in  the  museum  of 
Mr.  J.  D.  Clifford,  at  Lexington,  Ky. ;  it  inhabits 
the  Mississippi,  and  apparently  the  lower  part  of 
the  Ohio.  In  form  it  resembles  the  Lampsilis  ; 
but  its  lamellar  tooth,  instead  of  being  flexuous,  is 
curved  into  an  oblique  and  short  arch.  Although 
the  animal  was  living,  almost  all  the  epidermiswas 
destroyed,  even  to  the  white  nacre;  and  there 
was  perceptible  at  the  apices,  intermediary, 
smooth,  shining  and  olivaceous  nacre.  The 
wrinkles  deep  and  separated;  a  slight  oblique 
slope  posteriorly  ;  cardinal  tooth  very  much  fur- 
rowed ;  muscular  impressions  very  deep ;  fossule 
confluent ;  breadth  upwards  of  four  inches. 


SPECIES  XXI.     Obliquaria  interrupta — (Unio 
interrupta.) 

Shell  oval-elliptical,  somewhat  thick,  and  slight- 
ly ventricose  ;  epidermis  reddish  brown,  slightly 
4 


34 

wrinkled,  with  some  transversal  blackish,  inter- 
rupted bands ;  nacre  bluish  white.  Length  £ — 
diam.  £ — axis  £  of  the  breadth. 

Found  in  the  Kentucky  and  Ohio;  breadth 
about  two  inches  -,/ossule  visible  ;  lamellar  tooth 
slightly  rugose,  thick,  carinated  ;  apices  not  pro- 
minent. 


SPECIES  XXII.    Obliquaria  depressa — (Unio 
depressa.) 

Shell  oval-triangular,  thick  and  much  depress- 
ed; epidermis  wrinkled,  olive-brown,  with  oblique 
linear  scattered  black  points ;  nacre  bluish  ; 
somewhat  truncated  posteriorly.  Length  f — 
diam.  f — axis  ^  of  the  breadth. 

This  species  is  very  rare.  I  have  seen  only  one 
at  Evamville,  (Ind.)  and  deposited  the  only  spe- 
cimen I  possessed  in  the  museum  of  Mr.  J.  D. 
Clifford  of  Lexington,  (Ky.)  with  my  other  spe- 
cies. This  shell  is  almost  flat ;  breadth  one  and 
an  half  inch  ^fossule  visible  ;  teeth  striated;  the 
lamellar  tooth  carinated  and  sharp  ;  it  resembles 
the  sub-genus  Scalenaria. 


35 


SPECIES  XXIII.    Obliquaria  lineolata — (Unio 
lineolata.) 

Shell  nearly  round,  thick,  slightly  ventricose, 
somewhat  truncated  posteriorly  ;  epidermis  red- 
dish, slightly  wrinkled,  with  brown  lines ;  nacre 
white.  Length  £ — diam.  ^ — axis  ^  of  the 
breadth.  Apices  somewhat  prominent. 

Found  at  the  falls  of  the  Ohio  ;  breadth  about 
two  inches ;  posterior  portion  truncated,  plane, 
narrow;  muscular  impressions  deep  rugose;  la- 
mellar tooth  short,  thick,  carinated,  rugose,  almost 
straight. 

Second  Sub-genus^- ELLIPSARIA. 

Axis  extramedial ;  lamellar  tooth  straight ; 
ligament  straight ;  shell  elliptical. 


SPECIES  XXIV.   Obliquaria  ellipsaria — (Unio 
ellipsaria.] 

Shell  elliptical,  with  a  posterior  diagonal  angle; 
epidermis  somewhat  wrinkled,  reddish  olive; 
nacre  white ;  axis  almost  lateral.  Length  £ — 
diam.  | — axis  j  of  the  breadth. 

Var.  l.—fusca  entirely   brown  ;    breadth 
about  five  inches  ;  no  fossule ;  found  in 


36 


the   Kentucky  ;    resembles  the  genus 
Amblema ;  ligament  horizontal. 


SPECIES  XXV.   Obliquariafasciolaris  (Unio 
fasciolaris.) 

Shell  thick,  convex,  oval-elliptical,  posterior- 
ly attenuated  ;  epidermis  reddish,  almost  smooth, 
with  oblique  brown  bands  ;  nacre  white.  Length 
| — axis  i  of  the  breadth. 

Var.  1.  interrupta — bands  interrupted. 

Var.  2.  fuscata — almost   entirely  brown . 
bands  black. 

Var.  3.  obliterata — bands  almost  effaced ; 
shell  very  thick. 

Var.  4.  longa — length  f  of  the  breadth. 
This  species  is  common  in  the  Ohio,  Ken- 
tucky, Wabash,  &c.  and  appears  intermediate 
between  the  U.  interrupta  (species  21)  and  the 
Unio  nasutus  of  SAY.  The  animal  white,  similar 
to  that  of  the  Elliptic .  A  remarkable  character 
of  this  species  consists  in  the  cavity  of  the  valves, 
which  has  some  oblique  wrinkles.  Ligament 
somewhat  oblique  ;  apices  thick,  but  not  promi~ 
nent ;  cardinal  tooth  wrinkled,  thick  ;  lamellar 
tooth  thick,  short ;  fossule  visible  ;  muscular  im- 
pressions deep.  Breadth  sometimes  five  inches, 


37 


SPECIES  XXVI.   Obliquaria  verrucosa — (Unio 
verrucosa.) 

Shell  somewhat  thick,  elliptical;  obliquely 
sloped  posteriorly,  with  verrucose  wrinkles  ; 
epidermis  reddish  brown ;  nacre  white.  Length 
| — axis  i  of  the  breadth. 

This  species  is  remarkable  for  several  concen- 
tric ranges  of  unequal  warts,  flattened,  often 
white  by  rubbing ;  found  in  the  Ohio ;  breadth 
three  inches ;  cardinal  tooth  one  lobe  very  large, 
wrinkled,  the  other  small  and  smooth ;  muscular 
impressions  deep  and  smooth  ;  lamellar  tooth  ob- 
tuse •;  ligament  horizontal. 


SPECIES  XXVII.  Obliquaria  cuprea — (Unio 
cuprea.) 

Shell  thick,  elliptical,  obliquely  sloped  poste- 
riorly ;  epidermis  black,  almost  smooth ;  nacre 
copper  coloured.  Length  | — diam.  f — axis  ^ 
of  its  breadth. 

A  very  handsome  species ;  two  inches  in 
breadth  ;  nacre  singular,  brownish  flesh  inclining 
to  copper  colour,  changeable  to  purple.  I  found 
this  species  in  the  Monongahela  and  Potomac  ; 


4* 


38 

lamellar  tooth  short ;  no  fossule  ;  cardinal  tooth 
somewhat  wrinkled ;  ligament  horizontal.* 

Third  Sub-genus — QUADRULA. 

Form  square,  but  anteriorly  rounded,  slightly 
transversal . 


SPECIES  XXVIII.  Obliquaria  flava— (  Unio 
flava.) 

Shell  somewhat  thick,  convex,  and  sloping 
posteriorly ;  apices  slightly  prominent,  entire,  ru- 
gose ;  epidermis  nearly  smooth,  yellowish  brown  ; 
nacre  flesh  coloured.  Length  ^ — diam.  f — axis 
f  of  the  breadth. 

A  fine  species,  found  only  in  the  small  rivers 
falling  into  the  Kentucky,  Salt,  or  Green  rivers. 

*  The  Unio  nasutus  of  SAY,  ought  to  belong  to  this 
sub-genus;  and  the  following  species,  which  I  observed  in 
the  river  Hudson,  resembles  it  much :  may  not  this  be  a 
variety  ? 

Obliquaria  attenuata, — elliptical,  dilated,  attenuated^ 
with  a  posterior  slope;  ligament  horizontal;  epidermis 
rugose,  dark  brown ;  nacre  pale  rose  colour.  Length  1-2 
—diam.  1-4—  axis  1-4  of  the  breadth.  Breadtli  four 
inches. 


39 

Breadth  from  two  to  four  inches.  Animal  of  a 
deep  or  orange  yellow  colour,  with  a  large  cir- 
cular foot ;  in  other  respects  it  resembles  Ellipta. 
Shell  almost  yellow  when  young ;  the  lamellar 
tooth  carinated,  thin ;  cardinal  tooth  striated 
over  the  whole  surface;  ligament  oblique,  re- 
sembles the  unio  lineolata,  which  perhaps  ought 
to  be  placed  here. 


SPECIES  XXIX.     Obliquaria  Cyphia — (Unio 
Cyphia.) 

Shell  thick,  ventricose,  hunched ;  edge  flexuous, 
sloping  posteriorly  ;  epidermis  chestnut  brown  ; 
tubercles  with  flexuous  wrinkles;  nacre  white. 
Length  f— diam.  f — axis  f-  of  the  breadth. 
Breadth  two  to  three  inches. 

Shell  thickest  anteriorly,  with  large  wrinkles, 
and  some  oblong  tubercles;  a  large  oblique  longi- 
tudinal hunch,  or  boss  ;  cardinal  tooth  thick, 
striated ;  found  at  the  falls  of  the  Ohio. 


SPECIES  XXX.      Oliquaria  metanevra — (Unio 
metanevra.) 

Shell  thick,  ventricose,   hunched,  with    two 
marginal  sinuses  ;    one  posterior  and  the  other 


40 

terminal ;  sloped  and  nerved  posteriorly ;  epider- 
mis wrinkled,  brownish  with  dark  spots ;  nacre 
flesh  coloured.  Length  J- — diam.  T\ — axis  T\ 
of  the  breadth. 

A  small  and  rare  species ;  scarcely  more  than 
an  inch  in  breadth ;  found  in  the  Kentucky  ; 
shell  thin  posteriorly ;  nerves  obliquely  curved  on 
the  dilated  posterior  edge ;  one  or  two  hunches 
on  the  oblique  elevation ;  lamellar  tooth  short,  and 
broad ;  cardinal  tooth  striated  ;  no  fossule. 


SPECIES  XXXI.   Obliquaria  reflexa — (Unio 
reflexa.) 

Shell  thick,  convex,  hunched,  almost  rounded, 
truncated  posteriorly ;  inferior  edge  reflected, 
having  a  posterior  sinus;  epidermis  reddish,  al- 
most smooth,  rugose  posteriorly  ;  nacre  white, 
iridescent.  Length  £ — diam.  f — axis  ^  of  the 
breadth.  Breadth  one  and  an  half  inches. 

Attenuated  posteriorly  ;  two  hunches  on  the 
medial  elevation  ;  its  end  reflected  ;  wrinkles  se- 
parated, flexuous  in  the  form  of  sutures ;  lamellar 
tooth  prolonged,  carinated,  very  slightly  curved ; 
cardinal  tcoth  very  much  striated  ;  fossule  visible. 
Found  in  the  Kentucky  and  at  Letart's  rapids : 
may  not  this  species  belong  to  the  sub-genus 
Rotundaria  ? 


41 


SPECIES  XXXII.  Obliquaria  retusa — (Unio 
retusa.) 

Shell  thick,  convex,  without  elevations,  with 
a  slight  terminal  sinus;  epidermis  olivaceous, 
with  slight  wrinkles,  distant;  nacre  whitish. 
Length  £ — diam.  f — axis  £  of  the  breadth. 

A  small  species,  one  or  two  inches  broad ; 
rare  ;  found  in  the  Ohio  and  Kentucky ;  lamellar 
tooth  short,  carinated,-jfassttfe  not  visible. 


SPECIES  XXXIII.  Obliquariajlexuosa — (Unio 
fiexuosa. 

Shell  thick,  with  two  slight  elevations  and  a 
broad  flat  depression  between  them ;  sloped  pos- 
teriorly ;  epidermis  yellowish  brown,  lined  with 
brown  at  the  base,  with  flexuous  wrinkles,  some- 
what striated ;  edge  flexuous ;  nacre  bluish. 
Length  f — diam.  f — axis  f  of  the  breadth. 

Found  in  the  Kentucky,  Salt  and  Green  rivers 
— breadth  about  two  inches  ;  lamellar  tooth  short, 
almost  doubled  in  the  right  valve  ;  fossule  visi- 
ble ;  cardinal  tooth  small,  striated ;  muscular  im- 
pressions deep. 

Var.  1.  bullata,  with  some  broad  tuber- 
cles, flat  and  transversal  on  the  eleva- 
tions. 


42 


SPECIES  XXXIV.  Obliquaria  nodulata — (Unia 
nodulata.) 

Shell  thick,  ventricose,  nodulated,  sloped  pos- 
teriorly, and  truncated  vertically  ;  linear  longitu- 
dinal tubercles  upon  the  posterior  dilatation  ; 
epidermis  almost  smooth,  reddish  brown  ;  nacre 
iridescent.  Length  |£ — diam.  f — axis  ±  of  the 
breadth.  Breadth  one  inch  and  an  half. 

Found  in  the  Kentucky,  four  separate  nodo- 
sities distant ;  cardinal  tooth  thick,  striated;  mus- 
cular impressions  deep ;  lamellar  tooth  carinated. 
It  resembles  the  obliquaria  retusa;  both  have  the 
lamellar  tooth  very  slightly  curved. 


SPECIES  XXXV.  Obliquaria  quadrula—(Unio 
quadrula*} 

Shell  very  thick,  somewhat  ventricose,  with  an 
oblique  longitudinal  elevation  ;  oblique  furrow 
and  sinus  posteriorly;  epidermis  brown,  wrinkled; 
wrinkle?  striated  and  tuberculated  anteriorly  ; 
nacre  white,  roseate  on  the  borders.  Length  f — 
diam.  4 — axis  |  of  the  breadth.  Breadth  two  to 
three  inches. 

Common  in  the  Ohio  ;  with  some  oblong  trans- 
versal tubercles  on  the  elevation  ;  shell  somewhat 
sinuous  on  the  disk  ;  lamellar  tooth  short,  thick* 


43 

carinated,  striated ;  fossule  confluent ;  cardinal 
tooth  large,  striated ;  apices  truncated. 


SPECIES  XXXVI.   Obliquaria  bullata — (Unio 
bullata.) 

Shell  thick,  convex,  slightly  ventricose,  with 
an  oblique  furrow  and  sinus  posteriorly  ;  strewed 
with  irregular  confluent  tubercles ;  epidermis 
reddish  brown  with  flexuous  wrinkles  distant ; 
nacre  white,  flesh  coloured.  Length  f| — diam. 
f — axis  i  of  the  breadth. 

Found  at  the  falls  of  Ohio  ;  rare  ;  breadth  al- 
most two  inches ;  cardinal  and  lamellar  teeth 
like  preceding  species  ;  apices  rounded,  decorti- 
cated, but  not  truncated  ;  tubercles  often  bleached 
and  worn,  flattened,  pustulated,  of  various  forms. 

Fourth  Sub-Genus — ROTUNDARIA. 

Shell  rounded,  scarcely  transversal,  almost 
equilateral  ;  axis  almost  medial;  ligament  curved, 
short,  corneous/  lamellar  tooth  slightly  curved  ; 
cardinal  tooth  somewhat  anterior. 


44 


SPECIES  XXXVII.  Obliquaria  tuberculata— 
(Unio  tuberculata.'] 

Shell  very  thick,  ventricose,  slightly  truncated 
posteriorly ;  strewed  with  unequal  tubercles,  ex- 
cept anteriorly  ;  epidermis  wrinkled,  chestnut 
brown  ;  nacre  violaceous.  Length  |£ — diam. 
T6T — axis  T5T  of  the  breadth. 

A  species  common  in  the  Ohio  and  adjacent 
rivers  ;  breadth  three  inches  at  most ;  animal 
yellowish ;  cardinal  tooth  thick ;  very  rugose  ; 
lamellar  tooth  short,  carinated  ifossule  confluent  ; 
muscular  impressions  deep;  nacre  varies  from 
bluish  to  deep  purple. 


SPECIES  XXX VII I.   Obliquaria  Subrotunda— 
(Unio  subrotunda.) 

Shell    thick,    ventricose,    convex,    perfectly 

rounded ;  epidermis    almost   smooth,   yellowish 

brown ;  nacre  bluish  white.     Length  almost  equal 

to  the  breadth; — diam.  f — axis  T7F  of  the  breadth. 

Var.  1.  maculata,  strewed  with  dark  spots. 

This  species  is  common  in  the  Ohio  and  its 
tributaries  ;  remarkable  by  its  almost  equilateral 
and  not  transversal  form;  apices  prominent, 
rounded  ;  cardinal  tooth  thick  furrowed ;  lamel- 
lar tooth  carinated,  short,  and  somewhat  punc- 


45 

tured  j  fossule  confluent ;  anterior  muscular  im- 
pression punctured. 


SPECIES  XXXIX.    Obliquaria  pusilla —  (  Unio 
pusilla.) 

Shell  thick,  convex,  perfectly  rounded ;  epi- 
dermis smooth,  blackish ;  nacre  white.  Length 
« — diam.  %• — axis  ^  of  the  breadth. 

This  species  is  very  rare ;  found  in  the  lower 
part  of  the  Ohio ;  breadth  scarcely  more  than 
half  an  inch ;  resembles  in  shape  and  appearance 
the  Cyclas ;  cardinal  tooth  almost  smooth ; 
lamellar  tooth  linear.  May  this  not  be  a  young 
individual  ? 

Fifth  Sub-Genus— SCALENAKIA. 

Form  obliquely  triangular,  scarcely  transversal, 
but  very  inequilateral ;  axis  almost  lateral ;  car- 
dinal tooth  scarcely  anterior;  lamellar  tooth 
straight ;  ligament  oblique. 


46 


SPECIES  XL.  Obliquaria  obliquata — (Unio 
obliquata.) 

Shell  very  thick,  ventricose  ;  triangularly  oval  ; 
the  three  sides  arcuated ;  a  slight  oblique  longi- 
tudinal depression;  epidermis  almost  smooth, 
black  ;  nacre  purple  rose  colour.  Length  -^ — 
diam.  T67 — axis  ^  of  the  breadth. 

A  pretty  species ;  having  a  fine  purple  nacre 
with  iridescent  changes ;  found  in  the  Kentucky 
river ;  breadth  two  to  three  inches ;  lamellar  tooth 
long,  carinated ;  fossule  large,  distinct ;  cardinal 
tooth  wrinkled ;  muscular  impressions  deep ; 
apices  prominent,  truncated. 


SPECIES  XLI.   Obliquaria  triangularis  (Unio 
triangularis.} 

Shell  very  thick,  ventricose,  triangular  ;  poste- 
rior face  straight ;  apices  prominent ;  no  longi- 
tudinal depression ;  epidermis  brown,  almost 
smooth  ;  nacre  roseate  white.  Length  £ — diam. 
£ — axis  |  of  the  breadth. 

Var.   1 .  nigrescens — epidermis  blackish  : 
nacre  white. 

Common  in  the  Ohio ;  breadth  sometimes  four 
inches ;  cardinal  tooth  [very  large,  furrowed ; 


47 

lamellar  tooth  thick  carinated  ;  muscular,  impres- 
sions andfossule  deep. 


SPECIES  XLII.   Obliquaria  scalenia  ( Unio 
scalenia.) 

Shell  thick,  ventricose,  triangular;  sides  almost 
straight,  especially  the  posterior,  which  is  trun- 
cated ;  angles  rounded  ;  no  depression ;  epidermis 
smooth,  reddish  brown,  with  some  oblique  longi- 
tudinal brown  lines  ;  nacre  white.  Length  £ — 
diam.  £ — axis  -^  of  the  breadth. 

Found  in  the  Kentucky,  &c. ;  breadth  about 
two  inches  ;  cardinal  and  lamellar  teeth  furrow- 
ed, confluent ;  lines  narrow,  radiated,  distant. 

Sixth  Sub-genus — SINTOXIA. 

Shell  oblique-oval;  lamellar  tooth  and  ligament 
curved. 


SPECIES  XLIII.   Obliquaria  lateralis — (Unio 
later  alis.) 

Shell  thick,  ventricose,  oblique-oval ;  with  a 
slight  depression,  oblique  longitudinal,  curved, 


48 

narrow ;.  epidermis  wrinkled,  brown  ;  nacre  white. 
Length  % — diam.  f — axis  £  of  the  breadth. 

Breadth  two  to  three  inches.  Cardinal  tooth 
large,  striated  ;  fossules  visible  ;  lamellar  tooth 
thick,  carinated,  somewhat  doubled  in  both  valves. 


SPECIES  XLIV.  Obliquaria  sintoxia  (Unio 
sintoxia.) 

Shell  thick,  ventricose,  oblique-oval,  without 
depression ;  epidermis  black,  almost  smooth ; 
nacre  roseate.  Length  T9^— diam.  ^ — axis  f  of 
the  breadth. 

Found  in  the  Ohio,  rare ; — breadth  two  to 
three  inches ;  nearly  approaching  the  Obovaria 
pachostea,  Obliquaria  obliquata,  and  Obliquaria 
triangularis  ;  teeth  like  the  latter  species  ;  by  its 
form,  makes  the  transition  to  the  genus  Obovaria, 
which  follows. 

SECOND  SUB-FAMILY — Amblemidia. 

Shell  longitudinal ;  cardinal  tooth  under  the 
apex ;  lamellar  tooth  inferior  vertical ;  axis  ter- 
minal ;  wrinkles  zonal. 


49 

Sixth  Genus — OBOVARIA. 

Shell  oboval,  almost  equilateral ;  axis  nearly 
medial ;  ligament  curved  ;  cardinal  tooth  striated; 
lamellar  tooth  almost  vertical,  slightly  curved  ; 
marginal  contour  thickened ;  three  muscular  im- 
pressions ;  animal  similar  to  that  of  the  Unio,  but 
having  the  anus  below. 


SPECIES  XLV.   Obovaria  obovalis — (Unio 
obovalis.) 

Shell  thick,  ventricose,  rounded  inferiorly ; 
apices  prominent ;  epidermis  yellowish  brown, 
wrinkled ;  nacre  white.  Inferior  breadth  | — 
diam.  f  of  the  length — axis  medial. 

Common  in  the  Ohio  and  adjacent  rivers. 
Length  from  two  to  three  inches  ;  cardinal  tooth 
broad,  thick,  rugose  ;  lamellar  tooth  carinated, 
somewhat  oblique  :  muscular  impressions  deep. 


SPECIES  XLVI.   Obovaria  torsa — (Unio  torsa.} 

Shell  very  thick,  ventricose,  rounded  inferior- 
ly ;  epidermis  brownish  ;  nacre  purple  ;  medial 
breadth  f — diam.  f  of  the  length — axis  medial. 

5* 


50 

Var.     marginata  —  nacre   bordered, 
white. 

Species  rarely  found  in  the  Ohio,  but  more 
abundantly  in  the  small  rivers.  Length  from  one 
to  two  inches  ;  remarkable  by  its  apices,  which 
are  turned  in  front,  and  large  wrinkles,  which  are 
often  divided  in  two  by  a.  furrow ;  cardinal  tooth 
wrinkled;  fossule  visible;  lamellar  tooth  wrinkled, 
somewhat  oblique,  almost  double  even  in  the 
right  valve. 


SPECIES  XLVII.   Obovaria  striata — (Unio 
striata.) 

Shell  thick,  ventricose,  rounded  inferiorly; 
with  striated  wrinkles;  apices  scarcely  promi- 
nent ;  epidermis  brown ;  nacre  white  ;  medial 
breadth  |°— diam.  /T  of  the  length — axis  f  of 
the  breadth. 

Var.  1.    tuber culata — some    striated    tu- 
bercles on  the  wrinkles. 
Var.  2.  rosea — epidermis  reddish  brown, 

brown  anteriorly,  nacre  roseate. 
Length    about    three    inches ;    found   in   the 
upper  part  of  the  Ohio.     Animal  yellow ;  lamel- 
lar tooth  almost  vertical,  thick ;   cardinal  tooth 
furrowed ;  fossule  visible. 


51 


SPECIES  XLVIII.  Obovaria  pachostea — (  Unio 
pachostea.) 

Shell  extremely  thick,  ventricose,  rounded 
and  attenuated  or  flexuous  inferiorly;  apices 
somewhat  prominent ;  epidermis  brown,  slightly 
wrinkled ;  nacre  pale  violet  colour ;  border  flexu- 
ous. Medial  breadth  T95 — diam.  f^  of  the 
length ;  oblique  axis  f  of  the  breadth. 

A  remarkable  species,  with  an  interior  cavity, 
very  small  and  wrinkled ;  broad  cavity  under  the 
tooth ;  this  species  approaches  the  sub-genus 
Sintoxia,  genus  Obliquaria,  its  axis  being 
somewhat  oblique,  or  having  a  slight  posterior 
dilatation.  Found  in  the  Kentucky.  Length 
three  to  four  inches ;  lamellar  tooth  short,  vertical, 
obtuse  ;  cardinal  tooth  very  large  and  broad,  fur- 
rowed ;  fossule  visible. 


SPECIES  XLIX.   Obovaria  stegaria — (Unio 
stegaria.) 

Shell  thick,  ventricose,  rounded  inferiorly, 
slightly  imbricated,  by  the  large  separated  wrin- 
kles ;  apices  slightly  prominent;  epidermis  brown  ; 
nacre  white  ;  inferior  breadth  i-|  of  the  length, 
diam.  f  of  the  breadth ;  axis  medial. 


52 

Var.  1.  tuberculata — with  some  scattered 

tubercles. 

Var.  2.  fasciolata — fasciolated  with  green- 
ish brown ;  nacre  roseate. 
A  pretty  species,  rarely  longer  than  one  inch ; 
lamellar  tooth  somewhat  oblique,  straight,  obtuse  ; 
cardinal  tooth    striated ;   fossule   visible ;    rare 
in  the  Ohio. 


SPECIES  L.  Obovaria  cordata — (Unio  cordata.) 

Shell  thick,  ventricose,  cordated  inferiorly  by 
a  sinus  and  a  slight  depression ;  epidermis  smooth, 
brown ;  nacre  white ;  apices  somewhat  promi- 
nent ;  inferior  breadth  j-i  — diam.  §  of  the  length. 
Axis  medial. 

Var.  rosea — epidermis  blackish,  nacre 
roseate. 

A  small  handsome  species,  about  an  inch  long  ; 
found  in  the  Ohio,  &c. ;  rare  ;  lamellar  tooth 
sharp,  doubled,  slightly  oblique,  straight ;  cardi- 
nal tooth  furrowed ;  resembles  the  Obliquaria 
retusa. 


Seventh  Genus — PLEUROBEMA. 
Shell    oblong,    very   inequilateral;    ligament 


53 

straight,  or  rather  unilateral ;  axis  quite  lateral  or 
posterior ;  lamellar  tooth  vertical ;  cardinal  tooth 
slightly  wrinkled,  under  the  apex  which  is  supe- 
rior, terminal ;  four  muscular  impressions  ,•  animal 
similar  to  that  of  the  Unio,  except  anus  and  sy- 
phons, which  are  inferior. 


SPECIES  LI.  Pleurobema  mytiloides — (Unio 
mytiloides.) 

Shell  thick,  and  ventricose  superiorly,  attenu- 
ated at  both  ends ;  apices  prominent,  entire ;  epi- 
dermis almost  smooth,  reddish  brown,  with  some 
oblique  black  longitudinal  bands  ;  nacre  bluish ; 
lamellar  tooth  narrow;  breadth  f — diam.  £  of 
the  length — axis  £  of  the  breadth. 

This  species  rare;  found  in  the  Wabash; 
length  two  inches;  apices  somewhat  angular, 
very  prominent,  entire,  heart-shaped ;  lamellar 
tooth  very  straight;  muscular  impressions  and 
fossule  deep. 


SPECIES  LIT.  Pleurobema  cuneata — (Unio 
cuneata.) 

Shell  thick,  ventricose  superiorly,  oblong-oval, 
attenuated,  wedge-shape  inferiorly,  rounded  su- 


54 

periorly ;  epidermis  almost  smooth,  brown ;  api- 
ces prominent,  truncated ;  nacre  white,  irides- 
cent ;  lamellar  tooth  scarcely  straight ;  breadth  4 
— diam.  £  of  the  length — axis  %  of  the  breadth. 

Var.   1.   maculata — with    some    square 
black  spots,  scattered. 

Var.  2.   sulcata — with  a  slight  longitu- 
dinal depression. 

Common  in  the  Ohio,  near  Steubenville,  Ma- 
rietta, &c. ;  length  one  to  three  inches  ;  it  chiefly 
differs  from  the  preceding  species  in  its  form, 
its  lamellar  tooth  somewhat  curved,  &c. ;  animal 
pale  yellow;  muscular  impressions  profound; 
the  fossule  forms  a  fourth  impression,  which  is 
strongly  marked. 


Eighth  Genus — AMBLEMA, 

Shell  oval,  elliptical  or  square,  very  inequila- 
teral; axis  lateral,  posterior;  apex  lateral,  ob- 
lique, almost  superior ;  ligament  straight ;  lamel- 
lar tooth  vertical ;  cardinal  tooth  wrinkled,  late- 
ral at  the  apex ;  three  muscular  impressions, 
Animal  similar  to  the  Pleurobema, 


55 

SPECIES  LIII.  Amblema  olivaria~-(Unio 
olivaria.) 

Shell  thick,  somewhat  ventricose,  oval,  ellipti- 
cal ;  apices  scarcely  prominent,  almost  superior  ; 
epidermis  wrinkled,  olive-coloured ;  nacre  white, 
iridescent ;  lamellar  tooth  straight ;  breadth  f — 
diam.  £ — axis  ^  of  the  length. 

Var.  1.  dilatata — with  base  dilated  su- 
periorly. 
Var.  2.  fasciolaris — with  radiated  bands, 

brown. 

Found  in  the  Kentucky  ;  length  from  two  to 
three  inches  ;  this  species  is  intermediate  be- 
tween this  genus  and  the  preceding  genus. 
Fossule  visible  ;  cardinal  tooth  slightly  wrinkled  ; 
lamellar  tooth  thick  ;  ligament  of  a  gold  colour. 


SPECIES  LIV.  Amblema  rubra — (Unio  rubra.) 

Shell  thick,  ventricose,  somewhat  elliptical ; 
apices  scarcely  prominent,  with  a  slight  oblique 
or  broad  sinus  ;  furrow  posterior  ;  axis  almost 
lateral ;  epidermis  wrinkled,  blackish ;  nacre 
purple-red.  Length  -f — diam.  -| — axis  |  of  the 
breadth. 

Var.  1. — lineata — reddish  brown,  streaked 
with  brown  lines. 


56 

Var.  2. — pallida — brownish,  nacre  pale. 
Found  in  the  Kentucky  ;  about  two  inches  in 
length ;  it  bears  some  resemblance  to  the  Ellip- 
tio  and  Obliquaria  ellipsaria  ;  lamellar  tooth 
somewhat  obtuse,  very  slightly  oblique  ;  cardinal 
tooth  thick,  rugose ;  nacre  fine,  iridescent,  change- 
able with  blue  ;  nofossule  ;  animal  yellowish. 


SPECIES  LV. — Amblema  torulosa — (Unio 
torulosa.) 

Shell  thick,  somewhat  ventricose,  square-ellip- 
tical, with  a  slight  oblique  depression,  and  some 
nodules  ;  borders  flexuous  ;  epidermis  olive  co- 
loured, with  flexuous  wrinkles ;  nacre  bluish 
white.  Breadth  f — diam.  \ — axis  \  of  the 
length. 

Var.  angulata — depression  slight,  con- 
tour nearly  angular. 

Found  in  the  Ohio  and  Kentucky  ;  length  two 
inches  ;  two  or  three  nodules  on  the  oblique  ele- 
vation ;  lamellar  tooth  very  straight ;  no  fossule  ; 
cardinal  tooth  wrinkled. 


SPECIES  LVI.  Amblema gibbosa — (Unio  gibbosa.) 
Shell   thick,   ventricose,  oval-elliptical,   with 


57 

with  two  large  knotty  ribs,  oblique,  with  inter- 
mediary depression ;  edges  flexuous  /  epidermis 
reddish  brown,  almost  smooth ;  nacre  white. 
Breadth  f — diam.  4 — axis  f  of  the  length. 

Var.    1.  olivacea — epidermis     olive   co- 
loured, with  flexuous  wrinkles. 
Var.    2.     radiata — with    radiated     pale 

lines. 

Var.  3.  difformis — with  irregularly  form- 
ed hunches  (bosselures)  and  depres- 
sions. 

Very  common  in  the  Ohio  and  adjacent  rivers  ; 
length  from  one  to  three  inches ;  lamellar  tooth 
short,  oblique,  obtuse  ;  fossule  visible  ;  cardinal 
tooth  wrinkled  ;  apices  prominent,  heart-shaped. 
This  species  strongly  resembles  the  genus  Obli- 
quaria,  but  the  cardinal  tooth  is  under  the  opear, 
and  almost  inferior. 


SPECIES  LVII.  Amblema  costata — (Unio  costata.) 

Shell  somewhat  thick,  flattened,  slightly  square, 
with  large  longitudinal  ribs  a  little  oblique, 
flexuous,  dilated  into  a  wing  under  the  ligament, 
with  curved  oblique  ribs;  borders  undulated; 
epidermis  yellowish,  almost  smooth ;  nacre  white, 
iridescent.  Breadth  f — diam.  ^ — axis  -fa  of 
the  length. 
6 


58 

This  is  one  of  the  handsomest  shells  produced 
in  the  Ohio ;  rare  in  that  river,  but  less  so  in  the 
tributaries  of  the  Kentucky,  &c.  it  attains  al- 
most six  inches  in  length ;  nacre  tinted  with 
flesh  colour,  with  changes  of  violet ;  produces 
pearls  ;  I  have  seen  one  of  these  which  was  of 
an  oblong  form,  measuring  a  quarter  of  an  inch 
in  length.*  Apices  oblique,  wrinkled,  entire ; 
lamellar  tooth  long,  broad,  sharp,  compressed, 
slightly  oblique  ;  no  fossule  ;  cardinal  tooth 
striated  inferiorly.  Interior  borders  undulated  ; 
animal  yellow. 

THIRD  SUB-FAMILY — Anodontidea. 

Shell  transverse,  neither  cardinal  nor  lamellar 
teeth. 

Ninth  Genus — ANODONTA. 

Shell  elliptical  or  oval  ;  ligament  straight,  or 
curved ;  axis  extramedial  ;  three  muscular  im- 
pressions, slightly  apparent ;  contour  somewhat 


*  A  highly  respectable  friend,  and  zealous  conchologist, 
(JAMES  S.  CRAFT,  Esq.  of  Pittsburg,  Pa.)  possesses  a  pearl, 
that  is  very  little  inferior  in  lustre  and  beauty  to  the  ori- 
ental product ;  he  obtained  it  from  one  of  the  Ohio  Unios. 
—TRANS. 


59 

thickened  ;  animal  resembles  that  of  the  Unio. 
This  genus  may  be  divided  into  three  very  dis- 
tinct sub-genera. 

First  Sub-Genus — ANODONTA. 

No  lamellar  wrinkles  on  the  hinge.  This  sub- 
genus  comprehends  the  greater  part  of  the  spe- 
cies, viz  : — A.  Anatina,  A.  cygnea,  A.  radiata, 
A.  marginata,  SAY — A.  cataracta,  SAY, — besides 
the  two  following  species  which  I  observed  in 
the  Hudson  river. 

ANODONTA   ATBA. 

Shell  ventricose,  thin,  smooth,  elliptical,  black- 
ish; nacre  white  anteriorly,  reddish  brown, 
iridescent  posteriorly.  Length  £ — diam.  T52 — 
axis  i  of  the  breadth.  Breadth  does  not  exceed 
six  inches. 

ANODONTA    CUNEATA. 

Shell  slightly  ventricose,  thin,  elliptical,  at- 
tenuated posteriorly  ;  epidermis  wrinkled,  olive 
brown  ;  nacre  bluish  white.  Length  £— - diam. 
£ — axis  j  of  the  breadth.  Breadth  four  to  five 
inches. 


60 


Second  Sub-Genus — STROPHITUS. 

Hinge  with  a  marginal  projection  under  the 
apex. 

The  Anodonta  undulata  of  SAY  forms  this 
sub-genus,  which,  with  the  following,  might  be 
considered  a  genus. 

Third  Sub-Genus — LASTENA. 

Hinge  with  two  transverse  wrinkles,  obtuse, 
almost  lamelliform,  divergent  on  each  side  of  the 
apex;  ligament  straight,  membranous,  double, 
either  anterior  or  posterior. 


SPECIES  LVIII.  Anodonta  Ohiensis — (Lastena 
Ohiensis.} 

Shell  very  thin,  fragile,  translucent,  ventricose, 
elliptical,  somewhat  winged,  and  obliquely  trun- 
cated posteriorly  ;  apices  entire,  wrinkled  ;  epi- 
dermis smooth,  olive  coloured  or  brown  ;  nacre 
bluish.  Length  f — diameter  and  axis  £  of  the 
breadth. 

Var.  1.  radiata — olivaceous  copper  colour- 
ed, with  radiated  bands,  greenish, 


61 

Var.  2.  mridis — epidermis  of  a  fine  olive 

green  colour. 

Var.  3.  violacina — nacre  violaceous. 
Var.  4.  nigrescens — blackish  olive. 

Very  common  in  the  Ohio,  and  all  the  adjacent 
rivers.  Breadth  from  two  to  four  inches  ;  the 
lamellar  wrinkles  are  wholly  separated  from  the 
edges  of  the  shell ;  the  posterior  wing  is  com- 
pressed, angular,  sloping  and  brownish.  It  might 
perhaps  have  been  proper  to  name  this  species 
A.  mutabilis. 


SPECIES  LIX.  Anodonta  lata — (Lastena  lata.) 

Shell  very  thin,  fragile,  translucent,  convex, 
oblong-elliptical ;  apices  decorticated,  almost  in- 
visible ;  epidermis  brown,  blackish  anteriorly  ; 
nacre  bluish,  violet  under  the  apices.  Length  f 
— diam.  f — axis  £  of  the  breadth. 

Found  in  the  Kentucky,  &c.  rare  ;  breadth 
from  two  to  three  inches  ;  lamellar  wrinkles  at 
the  anterior  edge,  scarcely  apparent.  This  spe- 
cies ought  perhaps  to  form  another  sub-genus 
Hemistena,  or  be  united  to  the  first  sub-genus, 
but  that  the  ligament  is  double  or  extended  from 
the  two  sides  of  the  apices.  The  Lastence  ap- 
proach the  genus  Dipsas,  [of  LEACH.] 
6* 


62 


FOURTH  SUB-FAMILY — Alasmidia. 

Shell  transverse  ;  one  primary  anterior  tooth  ; 
no  lamellar  tooth. 


Tenth  Genus — ALASMIDONTA. 

Shell  oval  or  elliptical,  axis  extramedial  ;  three 
cicatrices  or  muscular  impressions ;  ligament 
straight,  imbricated,  &c. 


SPECIES  LX.  Alasmidonta  marginata. 

Shell  oval-elliptical ;  sloped  posteriorly,  with 
oblique,  obtuse  wrinkles  ;  epidermis  olive  brown, 
radiated  with  green,  and  wrinkled  zonally  ;  nacre 
bluish  white,  with  white  edges;  tooth  simple, 
compressed,  oblique.  Length  J  of  the  breadth. 

This  genus  and  species  were  established  by 
SAY  ;  (vide  Journal  of  the  Academy  of  Natural 
Sciences  of  Philadelphia,  vol.  i.  p.  459,)  who 
also  refers  to  this  genus  the  Unio  undulatus  (vide 
American  edition  of  Nicholson's  Dictionary,  ar- 
ticle Conchology  and  Tab.  III.  fig.  3.) ;  to  these 
must  be  added  also  the  following  species. 

The  above  described  species  is  found  in  the 
Scioto  river  ;  length  two  and  an  half  inches.  J 


have  not  seen  the  animal,  but  the  shell  I  have,  in 
the  cabinet  of  the  Academy. 


SPECIES  LXI.  Alasmidonta  costata. 

Shell  thin,  elliptical,  slightly  ventricose  ;  some- 
what sinuous  anteriorly  ;  undulated  with  broad 
curved  ribs  posteriorly  ;  epidermis  almost  smooth, 
olive  coloured  anteriorly,  blackish  posteriorly  ; 
nacre  white,  tinged  with  flesh  colour  ;  tooth  bi- 
lobed,  compressed,  oblique,  crenulated.  Length 
i — diam.  £ — axis  f  of  the  breadth. 

I  observed  this  fine  shell  in  the  museum  of 
Mr.  Clifford  of  Lexington,  Ky.  from  the  Ken- 
tucky river,  where  it  appears  to  be  rare  ;  breadth 
nearly  five  inches  ;  decorticated  anteriorly  and  su- 
periorly, but  very  entire  posteriorly  ;  ribs  very 
large  inferiorly  ;  ligament  horny  and  shelly,  im- 
bricated ;  tooth  decurrent ;  in  the  place  of  the  la- 
mellar tooth  a  small,  short,  oblique  angle  ;  small 
tubercles  in  the  interior. 

FIFTH  SUB-FAMILY — Cycladia. 

Shell  almost  equilateral,  two  lamellar  teeth  ; 
one  anterior,  the  other  posterior ;  often  one  or 
more  cardinal  teeth  intermediary,  under  the 
apex. 


64 

Eleventh  Genus — CYCLAS. 

Two  muscular  impressions;  lamellar  teeth 
oblique  ;  wrinkles  zonal ;  contour  not  thickened. 

This  genus  should  be  reformed,  notwithstand- 
ing the  labours  of  MEGERLE  and  FERUSSAC.  I 
propose  to  divide  it  into  four  sub-genera,  which 
may  perhaps  form  as  many  genera. 

1st.  Polymesoda.  Many  intermediary  teeth 
on  both  valves ;  shell  rounded  or  somewhat  trans- 
versal. Type  Cyclas  caroliniana,  Bosc,  &c. 

2d.  Phymesoda.  One  intermediary  tooth  in  one 
valve  ;  shell  somewhat  transversal.  Type  Cyclas 
lacustris — C.  dubia,  SAY,  &c. 

3d.  Amesoda.  No  intermediary  tooth  in  one 
valve,  at  least;  shell  slightly  transversal.  Type 
Cyclas  similis,  SAY.  C.  lasmampsis,  <$fc. 

4th.  Corbicula  (MEGERLE.)  Many  interme- 
diary teeth  in  both  valves ;  shell  triangular, 
somewhat  lengthened.  Type  Cyclas  hammalis, 
C.  fluviatilis,  &c. 


SPECIES  LXII.  Cyclas  lasmampsis — (Amesoda 
lasmampsis.} 

Shell  translucent,  ventricose,  slightly  rounded  ; 
wrinkles  close  together,  unequal,  more  distant 
and  broad  superiorly  ;  lamellar  teeth  flexuous,  the 


65 

anterior  twisted,  extended;  length  f — diam.  ^ — 
axis  T5¥  of  the  breadth  ;  nacre  bluish ;  breadth 
one  third,  or  half  an  inch ;  epidermis  variable, 
black,  blackish,  brown,  brownish,  olive ;  reddish 
brown,  horn  colour,  &c.;  apices  rounded,  not  pro- 
minent. Found  in  the  Ohio,  and  adjacent  rivers  ; 
no  intermediary  teeth. 


SPECIES  LXIII.  Cyclas  aqualis — (Phymesoda 
cequalis.) 

Shell  translucent,  ventricose,  rounded;  wrinkles 
close  together,  almost  equal,  obtuse ;  lamellar 
teeth  somewhat  flexuous,  short,  distant,  equal ; 
intermediary  tooth  oblique,  single  in  each  valve ; 
epidermis  corneous  ;  nacre  bluish.  Length  •§•— 
diam.  f  of  the  breadth ;  axis  medial. 

A  small  species  ;  length  one  quarter  of  an  inch, 
rare  ;  found  in  the  Ohio ;  internal  tooth  scarcely 
apparent,  obliquely  inclined  posteriorly ;  right 
valve  with  two  oblong  lamellar  and  almost  equal 
fossules ;  the  left  valve  with  a  corresponding  la- 
mellar tooth  ;  apices  rounded,  not  prominent. 


66 


In  this  place  I  shall  describe  two  species  that 
have  a  slight  relation  to  the  subject ;  viz.  a  tri- 
valve  shell  and  a  mytilus  from  Louisiana.  I  have 
added  also  some  species  that  have  been  omitted 
in  their  proper  places,  or  discovered  during  the 
progress  of  the  work. 

Twelfth  Genus — TREMESIA. 

Shell  tri-valve,  inequivalve,  principal  valve 
patelloid,  perforated  in  the  centre ;  the  small 
valve  closing  this  aperture,  as  an  operculum  f 
third  valve  inferior,  lateral;  the  animal  cepha- 
lous,  the  head  extensible  by  the  medial  opening, 
with  two  lateral  eyes  ;  no  tentacula. 

This  singular  genus  appears  to  be  the  type  of 
a  new  family  intermediate  between  the  Bra- 
chiopes,  Teredaria,  and  Patellaria;  like  the 
teredaria  it  has  three  valves,  but  a  head  like 
the  patellaria,  and  this  oculated  and  not  tentacu- 
lated head  is  central  instead  of  being  terminal. 


67 


SPECIES  LXIV.   Tremesia  patelloides. 

Principal  valve  rounded,  somewhat  conical, 
striated  concentrically,  and  tessellated  by  curved 
oblique  transversal  striaB ;  aperture  round ;  small 
valves  smooth ;  inferior  valve  oblique,  oboval ; 
animal  striated  flexuously  beneath,  acute  oppo- 
site the  inferior  valve  ;  head  truncated. 

Animal  very  singular  ;  which  I  announced  in 
the  American  Monthly  Magazine,  last  year, 
under  the  defective  name  of  Notrema.  It  is 
found  in  the  lower  part  of  the  river  Ohio,  attach- 
ed to  the  stones  by  the  base,  like  the  Patella  ; 
shell  brownish  fawn  coloured ;  opercular  valve 
brown,  glossy,  movable  ;  diam.  about  one  inch, 
height  half  an  inch. 


SPECIES  LXV.  Mytilus  recurvus. 

Shell  oboval,  cuneiform,  recurved,  with  longitu- 
dinal striae  of  three  lengths  ;  epidermis  blackish  ; 
nacre  violet ;  the  beaks  oblique,  with  a  decurrent 
angle  on  each  side  ;  the  inferior  and  interior  bor- 
der, striated,  crenulated.  Breadth  T72- — diam.  fa 
of  the  length. 

Found  in  the  Mississippi  near  New  Orleans — 


68 

length  from  one  to  two  inches ;  the  stria  are 
often  bifid  ;  the  gaping  part  oblong,  lateral. 


SPECIES  LXVI.  Ifnio  teres — (Elliptic  teres.) 

Shell  slightly  thick,  ventricose,  elliptical, 
widened,  truncated,  inferiorly,  posteriorly,  and 
obliquely  ;  epidermis  almost  smooth,  corneous ; 
nacre  white,  iridescent.  Length  about  J- — diam. 
| — axis  ^  of  the  breadth  ;  this  species  belongs  to 
the  sub-genus  Eurynia — vide  page  24. 

Found  in  the  river  Wabash ;  breadth  about 
three  inches  ;  slightly  sinuous  inferiorly  ;  apices 
eroded  ;  lamellar  tooth  long,  thin ;  cardinal  tooth 
crenulated,  decurrent. 


SPECIES  LXVII.  Obliquaria  sinuata — (Unio 
sinuata.) 

Shell  thick,  ventricose,  elliptical,  sinuous  in- 
feriorly ;  epidermis  reddish  brown,  wrinkled : 
nacre  white,  with  deep  oblique  interior  furrows. 
Length  •£ — diam.  i — axis  j  of  the  breadth. 
This  species  belongs  to  the  sub-genus  Ellipsaria. 
Vide  page  35,  found  in  the  Kentucky — breadth 
four  inches ;  lamellar  tooth  thick,  oblique, 


69 

straight,  wrinkled  \fossule  visible  ;  cardinal  tooth 
striated. 


SPECIES  LXVIII.  Obliquaria  atroviolacea — 
(Unio  atroviolacea.) 

Shell  somewhat  thick,  convex,  elliptical,  oval, 
and  posteriorly  attenuated ;  epidermis  blackish, 
almost  smooth  ;  nacre  very  deep  violet  colour ; 
border  dull  brown.  Length  ^ — diam.  £ — axis  ^ 
of  the  breadth.  This  species  belongs  to  the 
sub-genus  Ellipsaria,  Vide  page  35. 

A  handsome  species  with  a  fine  nacre;  breadth 
three  inches — found  in  the  Kentucky,  &c.  la- 
mellar tooth  carinated  straight  jfossule  confluent; 
muscular  impressions  deep  ;  teeth  wrinkled. 


SPECIES  LXIX.   Obliquaria  Cliffordiana — 
(Unio  Cliffordiana.) 

Shell  thick,  ventricose,  oval,  rounded ;  very 
long  posteriorly  ;  sloped  posteriorly ;  nacre  nearly 
smooth,  blackish,  pale  purple.  Length  £ — diam. 
f- -axis  i  of  the  breadth.  This  species  belongs 
to  the  sub-genus  Plagiola.  Vide  page  32. 

In  the  museum  of  Mr.  Clifford ;  found  in  the 
Kentucky.  Breadth  three  inches  ;  lamellar  tooth 
7 


70 

curved,  thick,  wrinkled  ',fossule  visible  ;  cardinal 
tooth  striated ;  apices  slightly  prominent,  decorti- 
cated ;  nacre  smooth,  saffron  colour. 


REMARKS. 

When  the  ligament  is  mentioned  in  the  prece- 
ding pages,  the  great  posterior  one  is  alluded  to  ; 
there  is  also  an  anterior  membranous  and  folia- 
ceous  ligament  in  all  these  shells,  which  is  very 
small  and  short,  in  the  elongated  or  rounded, 
and  larger  or  oblong,  in  the  elliptical  or  dilated 
shells. 

Having  more  carefully  examined  the  species, 
No.  48.  Obovaria  pachostea,  vide  page  51,  I 
have  discovered  that  it  belongs  to  the  genus 
Amblema,  to  which  it  must  be  united,  its  charac- 
ters are  as  follow  : — 

Amblema  antrosa,  very  thick,  somewhat  ven- 
tricose,  rounded,  flexuous  with  a  small  lateral 
sinus  inferiorly  ;  epidermis  brown,  lamellar ; 
nacre  violaceous,  pale,  undulated,  and  a  large 
cavity  under  the  bilobed  (cardinal)  tooth.  Breadth 
f — diam.  |-  of  the  length  ; — axis  almost  terminal. 


Page. 

Page. 

ALASM1D1A,  sub-family 

62  Scalenaria,  sub-genus 

-        45 

ALASMIDONTA,  genus 

02  Sintoxia,  sub-genus 

47 

costata 

03  Strophitus,  sub-genus 

60 

marginata  (Say)  6-2  TREMESIA,  genus 
AMBLEMIDIA,  sub-family      48                   patelloides 

66 
-        67 

AMBLEMA,  genus 
Amesoda,  sub-genus 

54  TRUNCILLA,  genus      - 
64  UNIODLE,  sub-family 

30 
14 

ANODONTIDIA,  sub-family 

58  Umo,  genus 

14 

ANODOXTA,  genus 

58             alatus  (Soy) 

30 

atra 

59             antrosa 

-        70 

cataracta  (Soy) 

59             atroviolacea 

cuneata 

53             attenu.ita,  note 

38 

cygnea 

59             aurata,  note 

20 

lata 

61             bullata 

43 

ohiensis 

60             cardium 

27 

var.  1. 

60             cariosus,  (Soy) 

30 

var.  2. 

61             caroliniana,  (Base) 

11.20 

var.  3. 

61             cliffordiana 

69 

var.  4. 

61             cordata 

52 

radiata 

53                       var. 

52 

undulata  (Say) 

60             costata 

57 

rfiimedia,  sub-genus 

23             crassa 

18 

CYCLADIA,  sub-family 

63             crassus,  (Say)  ; 

18.20 

CYCLAS.  genus 

64             cuneata 

53 

squalls 

65                          var.  1. 

54 

fluviatilis 

04                            var.  2. 

54 

hammalis 

64             cuprea 

37 

lasmampsis 

C4             cylindricus,  (Soy) 

16 

Corbicula,  sub-genus 

64             cyphia 

39 

Elliptic,  sub-genus 
Ellipsaria,  sub-genus 

15             decorticata 
35             depressa 

-        33 
34 

Eurynia,  sub-genus 

24             dilatata 

25 

LAMPSILIS,  genus 

26             ellipsaria 

-        35 

Lastcna,  sub-genus 

60                             var.  1. 

35 

Leptodea.  sub-genus 

21             elliptica 

23 

METAPTERA,  genus 

29             fasciata 

20 

Mytilus  recurvus 

67                          var.  1. 

20 

NOTREMA,  genus                   1 

2.  67                           var.  2. 

20 

OBLIQUARIA,  genus 

32                          var.  3. 

20 

OBOVARIA,  genus 

49              fasciola 

28 

PEDEFERIJJ,  family      - 

13             fasciolaris 

36 

Ptiymcsoda,  sub-genus 

64                                var.  1. 

36 

Plagiola,  sub-genus 

32                               var.  2. 

36 

PLEUROBEMA,  genus 

52                               var.  3. 

36 

Polymesoda,  sub-genus 

64                               var.  4. 

36 

Quadrula,  sub-genus 

38             flava 

38 

Rotundaria,  sub-genus 

43             flexuosa 

4J 

72 


Page.                                               Page. 
Uuio  rlexuosa,  var.  1.          -       41  Unio  quadrula           -       -       42 

fragilis 

22 

reflexa 

40 

var.  1. 

22 

retasa 

41 

gibbosa 

56 

rosea,  note 

28 

var.  1. 

57 

rubra 

55 

var.  2. 

57 

var.  1. 

55 

var.  3. 

57 

var.  2.      -        - 

56 

interrupta 

33 

scalenia 

47 

lateralis 

47 

stegaria 

51 

latissima 

25 

var.  1. 

52 

leptodon 

21 

var.  2. 

52 

var.  1. 

21 

sintoxia 

48 

var.  2. 

22 

sinuata 

68 

laevigata 

24 

solenoides 

26 

lineolata 

35 

var.  1. 

26 

megaptera 

29 

var.  2. 

26 

metanevra 

39 

var.  3. 

26 

mytiloides 

53 

striata 

50 

nasutus  (Say)  note 

38 

var.  1. 

50 

nervosa 

22 

var.  2. 

50 

nigra 

15 

subrotunda 

44 

var.  1. 

18 

var  1. 

44 

var.  2. 

18 

teres          - 

68 

nodulata 

42 

torsa 

49 

obliquata 

46 

var. 

50 

obovalis 

49 

torulosa 

56 

ochraceus,  (SayJ 

30 

var.  1. 

56 

ohiensis,  (Michaux) 

11 

triangularis 

46 

olivaria 

55 

var.  1. 

46 

var.  1. 

55 

triqueter 

31 

var.  2. 

55 

truncata 

31 

ovata 

27 

var.  1 

32 

ovatus  (Say) 

27 

var.  2. 

32 

pachostea 

51 

tuberculata 

44 

pallida,  note. 

28 

verrucosa 

37 

pictorum 
plicata,  (Lesueur) 
purpureus  (Say) 
pusilla 

21 
20 
20 
44 

viridis 
var.  1. 
var  2. 
zonal  is 

19 
19 
19 
24 

95=  Page 24,  3d  line  from  bottom,  for  Eurinea  read  Eurynia. 


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CI8RARY 

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JjUH   11  1941 

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